C function in a Python context

[castironpi at gmail.com]

On Feb 9, 3:04 pm, castiro... at gmail.com wrote:
> On Feb 9, 1:48 pm, castiro... at gmail.com wrote:
>
>
>
>
>
> > To write quick C things that Python won't do up to speed.  So it's got
> > a redundancy.
>
> > import ext
> > extA= ext.Ext()
> > extA[ 'enumfactors' ]= r"""
> >     int enumfactors( int a, const char* sep ) {
> >         int ret= 0, i;
> >         for( i= 1; i<= a; i++ ) {
> >             if( a% i== 0 ) {
> >                 ret+= 1;
> >                 if( i> 1 ) {
> >                     printf( "%s", sep );
> >                 }
> >                 printf( "%i", i );
> >             }
> >         }
> >         printf( "\n" );
> >         return ret;
> >     }
> >     """, ("i","i","s")
>
> > factorsn= extA.enumfactors( 209677683, ', ' )
> > print( "%i factors total."% factorsn )
>
> > import sys
> > sys.exit()
>
> > 1, 3, 23, 69, 131, 393, 3013, 9039, 23197, 69591, 533531, 1600593,
> > 3038807, 9116
> > 421, 69892561, 209677683
> > 16 factors total.
>
> '''Prototype implementation, slightly rigid.  If anyone knows how to
> compile and link without intermediate object file, and from a string,
> memory, or stdin, let me know.  Change first four lines.  If you are
> not using gcc, look at regenpyd().'''
>
> compilercommand=    'c:/programs/mingw/bin/gcc'
> pythondll=          'python30'
> pythonpathinclude=  'c:/programs/python/include'
> pythonpathlibs=     'c:/programs/python/libs'
>
> class Ext:
>     strctypes= { 'i': 'int', 's': 'const char*' }
>     class ExtElem:
>         def __init__( self, name, code, types ):
>             self.name, self.code= name, code
>             self.types= types
>     def __init__( self ):
>         self.__dict__[ 'exts' ]= []
>     def regenc( self ):
>         extcode= open( 'extcode.c', 'w' )
>         wr= extcode.write
>         wr( '#include <%s'% pythonpathinclude )
>         wr( '/Python.h>\n\n' )
>         for ext in self.exts:
>             wr( ext.code )
>             wr( '\n' )
>         for ext in self.exts:
>             wr( 'static PyObject *\n' )
>             wr( 'extcode_%s'% ext.name )
>             wr( '(PyObject *self, ' )
>             wr( 'PyObject *args) {\n' )
>             wr( '\t%s result;\n'%
>                 Ext.strctypes[ext.types[0]] )
>             for i, type in enumerate( ext.types[1:] ):
>                 wr( '\t%s arg%i;\n'%
>                     ( Ext.strctypes[type], i ) )
>             wr( '\tPyArg_ParseTuple(args, "' )
>             wr( ''.join( ext.types[1:] ) )
>             wr( '"' )
>             for i, type in enumerate( ext.types[1:] ):
>                 wr( ', &arg%i'% i )
>             wr( ' );\n' )
>             wr( '\tresult= %s( '% ext.name )
>             wr( ', '.join( [ 'arg%i'% i for i
>                 in range( len( ext.types[1:] ) ) ] ) )
>             wr( ' );\n' )
>             wr( '\treturn Py_BuildValue' )
>             wr( '( "%s", result );\n'% ext.types[0] )
>             wr( '}\n\n' )
>         wr( 'static PyMethodDef ExtcodeMethods[] = {\n' )
>         for ext in self.exts:
>             wr( '\t{ "%s", extcode_%s, '%
>                             ( ext.name, ext.name ) )
>             wr( 'METH_VARARGS, "" },\n' )
>         wr( '\t{NULL, NULL, 0, NULL}\n' )
>         wr( '};\n\n' )
>         wr( 'PyMODINIT_FUNC\n' )
>         wr( 'initextcode(void) {\n' )
>         wr( '\t(void) Py_InitModule' )
>         wr( '("extcode", ExtcodeMethods);\n' )
>         wr( '}\n\n' )
>         extcode.close()
>     def regenpyd( self ):
>         import os, os.path
>         if os.path.exists( 'extcode.pyd' ):
>             os.remove( 'extcode.pyd' )
>         import subprocess
>         retcompile= subprocess.call(
>             '%s extcode.c -c -I%s'%
>             ( compilercommand, pythonpathinclude ) )
>         assert not retcompile, 'Compiler error'
>         retlink= subprocess.call(
>             '%s -shared extcode.o -o extcode.pyd -L%s -l%s'
>             % ( compilercommand, pythonpathlibs,
>             pythondll ) )
>         assert not retlink, 'Linker error'
>         os.remove( 'extcode.o' )
>         os.remove( 'extcode.c' )
>     def __setitem__( self, key, value ):
>         code, types= value
>         self.exts.append( Ext.ExtElem( key, code, types ) )
>         self.regenc()
>         self.regenpyd()
>         import extcode
>         setattr( self, key, getattr( extcode, key ) )- Hide quoted text -
>
> - Show quoted text -

This is- and returns a list, of the enumerated factors.  Is it
starting to get bulky.


import ext
extA= ext.Ext()
extA[ 'enumfactors' ]= r"""
#include <string>
#include <vector>
using namespace std;
    PyObject* enumfactors( int a, const char* sep ) {
        string fmt= "[";
        vector< long > resv;
        for( int i= 1; i<= a; i++ ) {
            if( a% i== 0 ) {
                resv.push_back( i );
                fmt.append( "i" );
                if( i> 1 ) {
                    printf( "%s", sep );
                }
                printf( "%i", i );
            }
        }
        printf( "\n" );
        fmt.append( "]" );
        PyObject* res= PyList_New( resv.size() );
        for( int i= 0; i< resv.size(); i++ ) {
            PyObject* v= PyLong_FromLong( resv[i] );
            int succ= PyList_SetItem( res, i, v );
        }
        return res;
    }
    """, ("O","i","s")


factorsn= extA.enumfactors( 209677683, ', ' )
print( factorsn )